Heat deflectors for electric lamps or similar devices



Oct. 31, 1961 G. J. EDWARDS 3,007,059

HEAT DEFLECTORS FOR ELECTRIC LAMPS OR SIMILAR DEVICES Filed May 2, 1958 ITWVBTTtOT. Geotg e J. Edwards, b5 0% His ATTL' TTWH.

United States Patent 3,007,069 HEAT DEFLECTORS FOR ELECTRIC LAMPS R SIMILAR DEVICES George J. Edwards, Painesville, Ohio, assignor to General Electric Company, a corporation of New York Filed May 2, 1958, Ser. No. 732,640 2 Claims. (Cl. 313-42) My invention relates to electric lamps or similar devices comprising a sealed envelope or bulb containing a filament or other electric energy translation element which is heated during operation of the device, and more particularly to internal heat deflectors for such devices.

In certain types of electric lamps, particularly in gasfilled lamps of higher wattages, it is customary to arrange a heat deflector element in the form of a disc in the neck of the lamp envelope for the purpose of breaking up the hot convection currents and of reducing the radiant energy reaching the base, thus preventing overheating of the base end of the lamp. The disc is usually supported by the stem or mount structure which comprises a re-entrant glass stem tube extending into the bulb neck and having a pair of lead-in wires extending therethrough with portions of the wires sealed in a flattened press portion at the inner end of the stem tube. In one such construction, disclosed and claimed in Patent No. 2,624,019 to L. G. Leighton, the stem press is formed with transverse grooves and the deflector disc is provided with a radial slot extending from its periphery and having upstanding flanges at its margins fitting in the said grooves, the disc being assembled with the mount by sliding it later-ally across the grooves.

There is a need for heat deflectors in lamps having mounts comprising three or more lead-in wires which are arranged at the corners of a polygon so that the enclosing press or seal portion of the stem is of other than a mere flattened shape. For example, in the case of a threelead stem, the press portion is of Y-shaped cross section, and in a four-lead stem the press is of X-shaped cross section. It is accordingly an object of my invention to provide a heat deflector disc of such form as to permit its being mounted upon such stem presses without modification of the usual shape of the press and wtihout the need for clamps, rivets, welding, etc.

Generally speaking, in accordance with my invention, I provide a disc having its central portion apertured to encompass the press portion of the stem, the disc being slitted radially from the apertured portion to its periphery to provide for upstanding flaps spaced apart sufficiently to permit the disc to be slid laterally over the stem press, either by virtue of the spacing of the flaps or their inherent resiliency, the flaps preferably being closed after assembly, to lock the disc in place on the stern. When desired, the disc is also provided at the margin of the apertured portion with upstanding or angularly projecting tabs or spurs engaging with the side walls of the stem press to more securely lock it in place.

Further features and advantages of my invention will appear from the following detailed description of species thereof and from the drawing wherein:

FIG. 1 is a perspective view of a four-lead stem having a heat deflector disc assembled thereon;

FIG. 2 is a cross section through the press portion of the stem in FIG. 51;

FIG. 3 is a perspective view of the deflector disc prior to assembly onto the stem;

FIG. 4 is a perspective view of a four-lead stem with a modified form of disc construction; and

FIGS. 5 and 6 are plan and perspective views of the blank and the formed disc, respectively, prior to assembly on the stem;

3,007,069 Patented Oct. 31, 1961 FIG. 7 is a perspective view of a three-lead stem and further modified disc structure;

FIG. 8 is a section through the press portion of the stem of FIG. 7;

FIGS. 9 and 10 are plan and perspective views of the blank and the formed disc prior to assembly on the stem of FIG. 7;

FIG. 11 is a perspective view of a four-lead stem and further modified disc structure;

FIG. 12 is a plan view of the blank for the disc of FIG. 11; and

FIG. 16 is a plan view, partly in section, of a threelead stem carrying the disc of FIGS. 11 and 12.

Referring to FIG. 1 of the drawing, the stem or mount comprises a glass stem tube '1 and four lead wires 2 extending longitudinally through the tube and arranged at the corners of a square. Portions of the wires 2 are sealed in a press or seal portion 3 located at the inner end of the stem tube and formed by fusing the glass of the tube and compressing it between suitably shaped matrices on pinching jaws. The press portion 3 is preferably formed to an X-shaped cross section as shown in FIG. 2, with V-shaped indentations 4 between adjacent leads 2, and lobes 5 around the leads. The indentations 4 may extend the full length of the press 3 or they may terminate short of the upper end of the press so that said upper end is essentially square to provide lips '6 overhanging the upper ends of the indentations 4. The outer surfaces of the lobes 5 are tapered or convergent from the inner end of the press portion to a necked portion 7 of the stem tube 1. The stem usually also comprises a glass arbor tube or rod 8 extending axially from the press 3 and serving as an anchor for suitable support wires for a pair of filaments (not shown) connected to respective pairs of the lead wires 2 as is well known. Also, a glass exhaust tube 9 extends axially within the stem tube 1 and is fused at its inner end to the mass of glass forming the press 3 which is provided with an aperture 10 communicating with the exhaust tube 9 for subsequent evacuation and gas filling of the bulb or envelope 11 which is sealed to the flared end of the stem tube 1.

In accordance with the present invention, the stem 1 is provided with a heat deflector =12 in the form of a disc of resilient material, preferably sheet metal such as aluminum or steel about .006 inch thick, for example. The disc is provided with a central circular aperture 13 of a diameter to fit snugly around the necked portion 7 of the stem tube. The disc is also provided with a radial slit 14 extending from the aperture '13 to the periphery of the disc. FIG. 3 shows the form of the disc prior to assembly on the stem 1 with flaps or flanges 15 bent upward at an angle of about 55 from the surface of the disc along lines '16 more or less parallel to the slit 14 and spaced apart a distance approximating the diameter of the aperture 13; the margins of the slit 14 define the edges of the flaps 15.

The disc 12 is assembled on the stem 1 by sliding it laterally onto the neck portion 7 thereof with the flaps 15 foremost, the said flaps 15 being bent back due to their inherent resiliency to slide across the lobes 5. The flaps 15 are then preferably closed by bending them back down into the plane of the disc 12, as shown in FIG. 1, to securely lock the disc in place on the stem.

The stem 1 in FIG. 4 is of the same construction as shown in FIG. '1. However, in this case the disc 17 is provided with rectangular tabs 18, 19 and 20 (FIG. 6) at the margins of the aperture 21 therein and bearing resiliently against the sides of the lobes 5 to more securely retain the disc in place. As shown in FIG. 5, the tabs 18, 19 and 20 are formed by providing a radial slit 22 along a diameter 23, transverse slits 24 and 25 at opposite sides of a diameter 26 at right angles to diameter 23, and short slits 27 extending from the ends of slits 25 parallel to the diameter 23. The tabs 18 and 19 are formed by bending them up along the respective lines 28 and 29 to angles of about 8 90 from the surface of the disc. The tab 20 is bent up along line 30 at an angle of about 40-60". Flaps 31 and 32 are formed by bending up along respective lines 33 and 34 to angles of about 6070.

In assembly, the flaps 31 and 32 spread apart to slide across the lobes at opposite sides of the press 3 to bring the tabs 18 and 19 into resilient engagement with said sides of the press and the tab into engagement with a third side of the press 3. The flaps 31 and 32 are then preferably pressed to a fully closed position to firmly lock the disc in place.

In FIG. 7 there is illustrated a three-lead stem comprising a stem tube 1 and three lead wires 2 sealed in a press portion 3' of Y-shaped cross section with V-shaped indentations 4', and lobes 5 tapering to a constricted or necked portion 7 of the tube. The disc '35 comprises a pair of tabs 36 (FIG. 10) in the form of a trapezium and extending angularly from the disc surface into engagement with respective indentations 4' in the press 3'. The disc is securely locked on the stem around the necked portion 7 by closed flaps 37.

As shown in FIG. 9, the disc is formed to the shape shown in FIG. 10 for assembly onto the stern, by punching out a slot 38 of generally rectangular or butterfly shape to accommodate two of the three lobes 5' of the press 3. The tabs 36 and flaps 37 are formed by providing a radial slit 39 interrupted by the aperture 38, and a transverse slit '40 at the end of the radial slit. The tabs 36 are bent up at angles of about 55 along lines 41 which connect the respective ends of the transverse slit 40 with the proximate ends of slot 38, and the flaps 37 are bent up at about 55 along the lines 42 which extend from the ends of slot 38 approximately parallel to the radial slit 39.

It will be evident that the disc shown in FIGS. 1 and 3 may be employed with either the three-lead or the fourlead stem. Although particularly designed for a fourlead stem, the disc in FIGS. 46 may be used with a three-lead stem. Similarly, although the disc of FIGS. 7-10 is especially designed for a three-lead stem, it may be used with a four-lead stem. However, in FIGS. ,1-113 I have illustrated a more universal disc structure 43 which is adapted to fit securely on either a three-lead or a fourlead stem.

As will be apparent from an inspection of FIGS. 12 and 9, the disc 43 is formed somewhat similar to disc 35 except for additional slits 44 extending at an acute angle from radial slit 45 to form an additional pair of tabs 46. The tabs 47 may be bent up at an angle of about 45, and the tabs 46 and flaps 48 may be bent up at an angle of about 55 from the surface of the disc. In assembling the disc 43 onto the four-lead press 3 of stem 1 in FIG. 11, the flaps 48 and tabs 46 spread apart to slide across the square sides of the stem press 3, then a quarter turn of either the disc or the stern, about the axis of the stem, causes the tabs 46 and the tabs 47 to snap back into respective indentations so that the disc is quite securely held in place by engagement of the pairs of tabs 47 and 46 with each of the four indentations 4. Satisfactory results may be obtained by leaving the disc in that form with the flaps 48 at their original inclination of However, to even more securely fix the disc in place, the flaps 48 may be fully closed as shown in FIG. 11 with their sharp ends engaging one of the lobes 5.

When using the disc 43 with a three-lead stern having the Y-shaped press portion 3', as shown in FIG. 13, it may be firmly anchored in place by bending down both the flaps 48 and tabs 46 into the plane of the disc.

While I have shown and described in detail several species of disc construction comprising my invention, it will be evident to those skilled in the art that various further changes and modifications may be made within the spirit and scope of the invention as defined in the appended claims.

What I claim as new and desire to secure by Letters Patent is:

1. A heat deflecting disc of the class described for attachrnent to the stem press of an electric lamp mount structure, said disc having an elongated slot at the interior thereof centered transversely of its length about a given diameter of the disc, a radial slit having a first portion extending along said diameter normal to the length of said slot and from the periphery of the disc to said slot and a second portion extending along said diameter beyond said slot, the portions of said disc at either side of the first said portion of the radial slit being bent up at acute angles to the surface of the disc along lines extending from the ends of said slot substantially parallel to said first portion of the radial slit, and a short transverse slit extending across the end of said second portion of the radial slit, portions of said disc at either side of the said second portion of said radial slit being bent up at acute angles to the surface of the disc along lines joining the respective ends of said transverse slit with the proximate ends of said slot.

2. A heat deflecting disc of the class described for at tachment to the stem press of an electric lamp mount structure, said disc having a substantially centrally located elongated slot, a radial slit having a first portion extending along a diameter of the disc normal to the length of said slot and from the periphery of the disc to said slot and a second portion extending along said diameter beyond said slot, a pair of slits at opposite sides of and extending from the first said portion of said radial slit at acute angles thereto and defining a V pointed toward said slot, the portions of said disc at either side of said first portion of the radial slit being bent up at acute angles to the surface of the disc along lines extending from the ends of said slot substantially parallel to said radial slit, and a short transverse slit extending across the end of said second portion of the radial slit, portions of said disc at either side of said second portion of the radial slit being bent up at acute angles to the surface of the disc along lines joining the respective ends of the said transverse slit with the proximate ends of the said slot.

References Cited in the file of this patent UNITED STATES PATENTS 2,250,409 Krahl July 22, 1941 2,624,019 Leighton Jan. 4, 1952 2,664,513 Morgan Dec. 29, 1953 2,776,852 Morgan Jan. 8, 1957 2,777,082 May Jan. 8, 1957 2,813,993 Fridrich Nov. 19, 1957 

